Ultra high frequency electronic tube



Deq. 14, 1948. H. J. MCCARTHY ULTRA HIGH FREQUENCY ELECTRONIC TUBE Filed oet. 2,1, 1944 i INVENTOR.

TTORNEY Patented Dec. 14, 1948 ULTRA HIGH FREQUENCY ELECTRONIC rEUBE Henry J. McCarthy, Danvers, Mass., assignor to Sylvania Electric Products Inc., Salem, Mass., a corporation of Massachusetts Application October 21, 1944, Serial No. 559,727

5 Claims.

This invention relates to electronic tubes and particularly to such devices which act as resonators when supplied with an external source of high frequency current, and when applied to certain uses are known as gas switching tubes.

It is an object of the invention to provide a tube of the type indicated in which the leakage energy at its discharge may be held substantially constant over a considerable range of adjustment of its resonant frequency.

A further object of the invention is to provide an electronic tube having a discharge gap as part of its resonating system which remains invariable throughout a substantial range of frequency adjustment.

Other objects and features will more fully appear from the following description in connection with the accompanying drawing.

The invention may be applied to a number of different types of electronic tubes and is herein applied to an ultra high frequency electronic resonating device suitable for use as a gas switching tube.

The tube illustrated herein is similar to that described in a copending application filed by the present applicant on. May 24, 1944, entitled Ultra high frequency electronic tubef.7 and bearing Serial Number 537,145 now Patent Number 2,454,741.

The tubeis made of a highly conductive metal such as copper and comprises a body portion having a resonating chamber therein and at least one coupling window, I'he discharge element of its oscillating system is formed by a pair of coneshaped electrodes one of which is hollow.

The cones are arranged with their slightly truncated apex ends opposed and in alignment. The hollow cone has a conical chamber terminating in a small aperture at its apex end within which is received a straight rod of uniform diameter which is anchored in the end of the other cone. The hole in the hollow cone is larger than the rod thus a gap is formed between the rod and the peripheral edge of the hole. The cone having the rod is axially adjustable to obtain a required frequency adjustment.

The tube is coupled in a wave guide system and functions in a manner to be described hereinafter,

To present a better understanding of the nvention a particular embodiment thereof is described and illustrated in the drawings in which:

Figure 1 is a perspective view of a preferred embodiment of the invention;

Figure 2 is a longitudinal sectional View of the device; and

Figure 3 is an enlargedrdetail view of the parts directly involving the invention.

Fig. 4 is a detailed perspective view showing a modified construction for the cone shaped electrodes.

In the type of electronc device to which the present invention is applied it is desirable that the discharge element of its resonating system be of special construction so arranged that it presents a constant gap across which the discharge takes place when the tube becomes ionized. The gap remains constant despite adjustment 0f the resonant frequency of the tube.

The tube to which the invention is applied has an envelope I of copper or other electrically conductive material enclosing a resonance chamber 2 which is provided with a pair of coupling windows 3 and 4 through which a high frequency wave may pass into and out of the tube. The windows may be coupled to suitable wave guides 5.

Within the chamber 2 a pair of cone-shaped electrodes 6 and 'l are received. The cone 1 is fixed in position and has a cone-shaped axial chamber the apex end of which opens into the slightly truncated apex end of the cone to present the aperture 8. The other cone 6 desirably is solid and is disposed with its slightly truncated apex end in alignment with the inner end of the cone 'l and is spaced a short distance therefrom. The cone 6 is adjustable axially toward and from the cone l. This may be accomplished in any suitable manner. As shown in the drawings the cone 6 is secured to a flexible diaphragm 9 which in turn is hermetically sealed in the envelope and forms a closure for the chamber 2.

The outer face of the diaphragm 9 has secured thereto an adjusting screw IG. The screw I0 has thereon a differential nut Il which in turn has threaded engagement with a plug l2 xed in the envelope I. The position of the cone 6 is nely adjusted by rotating the nut l l as by means of a screw driver placed in the slot i4.

Desirably a glass exhausting chamber l5 is sealed to the envelope and communicates with the chamber 2 through the opening in the cone l. The chamber I5 is provided with an exhaust tube by means of which the tube is evacuated of air and through which suitable gas may be introduced A keepalive I6 may be provided having its inner end extending into the cone 'l but spaced from the rod l1. The outer end of the keepalive I6 is extended outside of the chamber l5 for connection to a source of energy.

'Ihe tip of the cone has anchored therein a metallic rod I1 of uniform and relatively small 3 diameter of the order of ten one thousandths of an inch. The rod is desirably axially disposed in the cone II and projects a short distance into the aperture 8 in the cone 'I but not into close proximity to the keepalive I6. The diameter of the aperture 8 is larger than the diameter of the rod II an .amount sullicient to establish the desired gap between the rod and t'he .cone 'I. In operation the frequency of the tube must be adjusted to adapt it to the particular circuit .to

which it is coupled. To do this the cone 6 is moved by the adjusting nut IfI. l'ln so doing the resonant frequency of the tube is varied but the discharge gap remains constant.

The ends of the cones 6 ,and I ,may have suitable structure. An effective variation :of fthe structure above described is `.that illustrated in Figure 4 in which the apex ends ofthe cones are shaped as shown to present coacting discharge gap members I8 and I9 representing opposed and parallel faces 20 and v2l .across whicndischarge takes place. The planes Y,of lthe faces v,2.1) .and .21| also Alie parallel vto the axis of the cones .along which they Aare movedto .tune the tube. Throughout the range of tuning of the tube therefore .the gap members I8 :and kI9 presenting opposed and When the tube is used for certain purposes and is supplied -With a substantial vvolume Lof .energy its resonant system is designed .to produce ionization `and discharge vat the .point of minimum gap which exists between the rod :Il .and the `cone 1 i-n `one case and between the faces 20 and .2l in the other case. Itis very ydesirable that the amount .of leakage energy passing through the discharge jpath should remain substantiallyconsta-nt `throughout the .range .of frequencies Ato which the tube ymay be adjusted. .By making the discharge path constant the energy passing through it is .also held Asubstantially constant lat Whatever the .operating frequency of Vthetube-may be.

What I claim is:

il. electronic resonator ltube vcomprising an envelope, ra gas filling therein, 'a cavity resonator within ysaid envelope, va pair .of frequency vadjusting electrodesspaced apart and forming a part-of said resonator, means acting .0n one lof .saidelectrodes to Irn'ovefsaid electrode axially withrespect to :the .other electrodeito tune *the resonator, Aan extension .on 'one :of said tuning .electrodes and spaced radially from the other electrode a predetermined discharge distance and having a surface parallel to the axis of said other electrode, whereby the discharge distance remains constant as the means actingfon one of said electrodes moves said electrode axially to tune the resonator. 2. The ,combination Kof v.claim .g1 in which the discharge 'distance betweenthe electrodes is less than the minimum distance between the frequency 4,determining portion of the electrodes.

3. The combination of claim 1, in which the frequency adjusting electrodes are conical, and the extension on one of said electrodes cylindrical andfi'ltting `into an @opening at the apex of the .other ele ctrode.

4.`The l.oombination of claim 1, an extension on the other ofsaid electrodes, and in which the frequency adjusting electrodes are conical, the extension on said electrodes having flat surfaces parallel to andin radial juxtaposition with each other.

.5. .An .electronic ,resonator tube ,comprising 4an envelope, `a-gasilling therein, vapair of frequency adjusting electrodes in axial juxtaposition -r.tlflerein .and-spaced apartbne of said ,electrodes'being .axially 1movable, .an extension on `one y.of said electrodes .and .having a surfacenparallel to the axis of .said electrode .andfspaced from the .other electrode .a predetermined `discharge .distance, whereby said distance remains constant with axial movement of .said movable ielectrode.

HENRY J. yMCCARTHY.

REFERENCES CITED The following references are of recordfinthe file of this patent:

'UNITED STATES PATENTS 

